Fabrication of wear resistant abrasive cutting blades



June 4, 1963 G. o. GRIFFIN ET AL 3,092,094

FABRICATION OF WEAR RESISTANT ABRASIVE CUTTING BLADES Filed March 14, 1960 2 Sheets-Sheet 1 ka/2&5 0. iQ/FF/IV,

ash/02m 3. .ElZwsx/Am INVENTORS.

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June 4, 1963 G. o. GRIFFIN ET AL 3,092,094

FABRICATION OF WEAR RESISTANT ABRASIVE CUTTING BLADES Filed March 14, 1960 2 Sheets-Sheet 2 42 $503650. EQ/FF/M, Z EZzswopn/ .9. JLIVSHAIZ g INVENTORS United States atent ()ffice mama: Patented June 4, 1963 3,092,094 FABRICATION OF WEAR RESISTANT ABRASIVE CUTTDIG BLADES George 0. Griflin, Newport Beach, and Ellsworth S. Hanshaw, Baldwin Park, Calif., assignors to Trurun, Inc.,

Huntington Beach, Calif.

Filed Mar. 14, 1960, Ser. No. 14,593 19 Claims. (Cl. 12515) The present invention relates generally to abrasive blades for cutting hard materials; more particularly, the invention relates to the provision of wear resistant side surfaces on cutting blades having peripheral abrasive cutting edges.

Blades or wheels having abrasive cutting elements or segments have long been utilized for cutting or sawing various hard materials, such as concrete or rock, and various methods have been utilized for fabricating such blades. A major problem associated with such blades is that the service life of the cores or supporting central portions of the blades is often shorter than the service life of the abrasive segments, because of blade failure resulting from erosion or undercutting of the side surfaces of the core near the abrasive cutting segments.

Various attempts have been made in the prior art to alleviate the problem of erosion or undercutting of blade cores in order to increase the the service life of the cores to at least equal the service life of the abrasive segments. The methods and structures involved in these attempts have not been fully effective or entirely successful in solving the problem and have involved certain shortcomings and disadvantages. Undesirable complications have been introduced into the fabrication of abrasive cutting blades, and undesirable features have often been introduced into the finished cutting blades.

The present invention provides a novel method of fabricating abrasive cutting blades and provides a novel abrasive cutting blade wherein hard wearing side surfaces are appropriately positioned to eliminate excessive Wear and insure a core service life comparable with the service life of the abrasive segments. The method does not involve undesirable or undue complications, and undesirable features are not introduced into the finished abrasive blades.

According to the method of the invention, a groove is cut into each side surface of a blade core near the periphery at the areas Where excessive wear and erosion normally occur. Hard facing material is welded into each of the grooves in succession, in accordance with particular sequences of steps hereinafter described. A rim portion of the core between the groove and the periphery is then removed, as by grinding. The steps of the method may preferably include the gumming or slotting of the core by cutting a plurality of spaced slots extending inwardly from the edge. Abrasive cutting segments, such as diamond segments, are then attached to the periphery of the blade core to produce a finished abrasive cutting blade.

The hard facing materials, which may for example be tungsten or chromium alloys, provide extraordinarily hard wearing side surfaces. The service life of a blade core is therefore comparable with or exceeds the life of the abrasive cutting segments. The thickness of the blade core is not increased by the method of the invention. Areas of the core side surfaces which are most subject to Wear are covered with hard facing material. Any continuing wear on these areas is borne by the hard facing material rather than the metal of the core itself and erosion is minimized.

It is therefore an object of the present invention to provide a new and useful method of fabricating abrasive cutting blades.

An object of this invention is the provision of an abrasive cutting blade core having a service life comparable with the service life of abrasive cutting segments attached to the core.

It is an object of the invention to provide an abrasive cutting blade wherein a novel and improved core has a service life comparable with the service life of abrasive cutting segments attached to the core.

An object of the present invention is the provision of an abrasive cutting blade which alleviates or obviates the problem of excessive wear and erosion of the blade core inwardly of abrasive cutting segments on the core periphery.

It is an object of this invention to provide a method of fabricating an abrasive cutting blade which increases the service life of the blade core by providing grooves in the side surfaces adjacent the core periphery and welding hard facing material into the grooves to resist wear in service.

It is an object of the present invention to provide a method of fabricating abrasive cutting blades in accordance with the foregoing object, wherein a first hard facing material is welded into a groove on one side surface, and a second hard facing material having a lower melting point is thereafter welded into a groove in the opposite side surface, thereby preventing fusion or sagging of the first facing material.

Another object of this invention is the provision of a method of fabricating abrasive cutting wheels in accordance with the foregoing objects, wherein an annular portion of the core radially outward from the grooves is removed and abrasive segments are attached adjacent to the hard facing material.

Other objects, features and advantages of the present invent-ion will become apparent to those versed in the art from an examination of the following description, the appended claims and the accompanying drawings, wherein:

FIGURE 1 is a perspective view of the core of an abrasive cutting blade utilized in the method of the present invention;

FIGURE 2 is a fragmentary sectional and perspective view taken at line 2-2 of FIGURE 1;

FIGURE 3 is a partial elevational view showing an annular groove out near the periphery of the blade core of FIGURE 1;

FIGURE 4 is a fragmentary sectional and perspective View taken at line 44 of FIGURE 3;

FIGURE 5 is a view similar to that of FIGURE 4 and showing hard facing material welded in the groove in the core;

FIGURE 6 is an elevational view showing radial slots cut inwardly from the periphery of the core;

FIGURE 7 is a fragmentary sectional and perspective view taken at line 77 of FIGURE 6, showing the core after the removal of excess hard facing material;

FIGURE 8 is a fragmentary sectional view showing the core with a second annular groove cut in the side of the core opposite from the groove shown in FIGURES 3 and 4;

FIGURE 9 is a partial elevational view, showing the slotted core with hard facing material welded into the second groove shown in FIGURE 8;

FIGURE 10 is a fragmentary sectional view taken at line 101i) of FIGURE 9;

FIGURE 11 is a partial elevational View showing the core with additional radial slots cut therein;

FIGURE 12 is a view similar to the views of FIG- URES 8 and 10, showing the core after the removal of excess hard facing material at the second groove;

FIG. 13 is a fragmentary perspective view showing the core after removal of an annular rim portion radially outward of the annular grooves and the facing materials;

FIGURE 14 is a fragmentary sectional view taken at line 14-14 of FIGURE 13;

FIGURE 15 is a partial elevational view of the finished abrasive cutting blade of FIGURE 14 with abrasive segments mounted on the periphery between adjacent slots;

FIGURE 16 is a fragmentary perspective view showing a finished abrasive cutting blade with abrasive segments secured to the core periphery;

FIGURE 17 is a fragmentary sectional view taken at line 17-17 of FIGURE 15;

FIGURES 18 through 22 are fragmentary sectional views illustrating steps of a modified form of the method of the present invention; and

FIGURES 23 through 26 are fragmentary sectional views illustrating steps of another modified form of the method of the invention.

Referring to the drawings, FIGURE 1 through 16 illustrate a preferred embodiment of the method of the present invention for fabricating wear resistant abrasive cutting blades. FIGURES 1 and 2 show a circular steel core blank having a central opening 12 and side surfaces 14, '16. The core is preferably formed of a type of steel which is heat treatable to a required hardness. For example, it may be of SAE 4135* steel which is treatable to a hardness of Rockwell C 30-35.

An annular depression or groove .18 is cut, as by a lathe, in side 14 of the core blank near the periphery and spaced therefrom, as indicated in FIGURES 3 and 4. The groove defines an annular rim portion of the core, as shown.

The blade core blank is then preheated, as by a torch, and a body of hard facing material 20 is secured in the groove 18 by welding, as indicated in FIGURE 5. During the welding process, the annular rim portion of the core serves as a dam in retaining the facing material while it is in a fluid state. The material 2% may for example be a tungsten-cobalt base alloy having a melting point of approximately 2600 Fahrenheit. The Welding may be done either manually or automatically, and any of various conventional welding processes may be utilized, such as oxygen-acetylene welding, atomic hydrogen welding, Heliarc welding, electrical metallic Welding or furnace welding.

After the welding of the hard facing material 20, the core blank 10 is preferably allowed to cool slowly to insure against cracking of the hard facing material. Slow cooling may be accomplished by placing the core blank in an insulating material such as vermiculite, by cooling in a furnace, or by other means. It has been found in practice that the blank may preferably be allowed to cool from a temperature of 12001500 Fahrenheit to room temperature in approximately eight hours. Slow cooling in this manner has been found to provide good insurance against cracking of the welded hard face material during the fabrication of an abrasive cutting blade and during the service life of the blade.

As illustrated in FIGURES 6 and 7, radial slots are cut inwardly from the periphery of the core blank in equally spaced relation along the circumferential edge. The slots may be of any appropriate dimensions; for example, they may be inch wide, /1 inch deep, and spaced at 3 inch intervals. The purpose of cutting the slots or gumming the blade core is to permit expansion and contraction of the core during its fabrication and during its service life without cracking of the welded hard facing material.

Next, the hard facing material 20 is ground to remove excess material to provide a material surface which is co-planar with the side surface 14 of the core blank, as shown in FIGURES 7 and 8.

A second annular depression or groove 24, similar to groove 18, is then cut in the side surface 16 of the core, as indicated in FIGURE 8. The grooves 18, 24 together define a peripheral annular rim 32 and a reduced core portion 34, as shown.

A second body of hard facing material 26 is next welded in the second groove 24, as indicated in FIG- URES 9 and 10. The rim 32 serves to retain the material 26 while it is fluid. This second facing material is preferably an alloy having a lower melting point than the hard facing material '29 on the opposite side 14 of the core blank. The lower melting point permits the welding of the material 26 without requiring such a degree of heat that fusion or sagging of the hard facing material 20 on the opposite side of the core might occur. The facing material 20 therefore retains its corfiguration and remains in the groove 18. By way of example and not by way of limitation, with a tungsten-cobalt base alloy 20 welded in groove 18, a chromium-borite-nickel alloy with a melting point of approximately 1400 Fahrenheit might be used in groove 24. It will be understood that the specific hard facing materials mentioned herein are essentially exemplary, and that the invention is not to be construed as being limited to specific materials. The essence of the invention resides in the method of fabrication and in the abrasive cutting blade produced by the method.

After the hard facing material 26 is welded in groove 24, the blade core is slowly cooled, in the manner hereinbefore described relative to the cooling after the welding of the hard facing material 20.

Preferably, a second series of radial slots 28' are then cut inwardly from the periphery of the blade core. Each slot 28 is spaced between each adjacent pair of the previously cut slots 22, as shown in FIGURE 11. The slots 28 are wider than the original slots 22. Each slot 22 is cut to the greater width of slots 28, for example /8 inch. It will therefore be observed that in the exemplary embodiment herein described, there are provided a plurality of /8 inch slots equally spaced about the circular periphery of the blade core at 1 /2 inch intervals.

Excess material is removed from the hard facing material body 26 so that its surface is co-planar with side surface 16 of the core. This is illustrated in FIGURE 12.

The core is heat treated to a desired hardness. For example, it may be treated to a hardness of Rockwell C 30-35 by quenching in a bath at 1600 Fahrenheit. The core is then subjected to a tempering operation, which may preferably consist of heating the core to 900975 Fahrenheit and allowing it to cool to room temperature.

The original central opening 12 in the core is then reamed to a larger selected size to produce a final enlarged central opening 30, shown in FIGURE 15.

Next, the annular peripheral rim 32 radially outside the welded facing materials 20, 26 is removed, as by grinding, and the core may then be tempered to remove grinding stresses. The grooves 12, 24 thus become annular peripheral depressions in the core. As shown in FIGURES 13 and 14, the circumferential edges of the hard facing materials 20, 26 and the circumferential edge of the reduced core portion 34 define a peripheral edge surface 36 of the final blade core.

Diamond abrasive cutting segments 38 are then attached to the peripheral edge surface 34, as shown in FIGURES 15, 16 and 17. Each of the abrasive cutting segments is positioned between a pair of adjacent slots and is radially circumjacent the hard facing materials 20, 26. The abrasive segments may be attached in conventional manner by brazing utilizing silver solder, by bonding, or by other appropriate means.

The fabrication of abrasive cutting segments does not constitute a part of the present invention. Typically such segments are produced by powdered metallurgy by placing diamonds in a matrix, such as a tungsten-carbide matrix, and by sintering with heat and pressure. Appropriate methods of forming diamond abrasive segments are described in United States Patents Numbers 1,895,926 and 1,904,049.

It is to be understood that variations may be made from the foregoing steps without departing from the scope of the present invention. Examples of such variations are shown in FIGURES 18 through 26. In FIGURES 18 through 22, there is illustrated a sequence of steps wherein both grooves 18, 24 are out before the hard facing material 20 is welded in groove 18. Any scale or oxidation produced in groove 24 by the heat of the welding in groove 18 is then removed by sand blasting, by picfling in acid, or by other appropriate means. The facing material 20 may be ground to provide a smooth surface immediately following its welding and cooling, or the grinding may be performed as a later operation in the fabrication of the abrasive blade. Rim portion 32 is removed and abrasive segments 38 are attached to the peripheral edge surface of the core in the manner hereinbefore described.

FIGURES 23 through 26 illustrate a series of steps wherein annular depressions 38, 40 are first cut to the edge of the core blank and define a reduced portion 42. Facing materials 20, 26 are welded in depressions 38, 40, respectively. Peripheral portions of the facing materials and of reduced portion 42 are then removed, as by grinding, and abrasive segments 38 are attached to the core.

The final abrasive cutting blade or wheel according to the present invention is best shown in FIGURES 15 and 16. The abrasive cutting blade comprises a core having an outer portion 34 of reduced thickness on both sides of which hard facing materials are welded. Abrasive diamond segments are mounted on the peripheral edge surface 36 of the core adjacent to the hard facing materials. The hard facing materials 20, 26 are integral-1y connected with the core 10 and with the abrasive segments 38. The facing materials are positioned to resist wear and erosion radially inward from the abrasive segments. A plurality of radial slots are spaced about the periphery and extend inwardly therefrom.

Those versed in the art will appreciate that the present invention achieves the objects and realizes the advantages hereinbefore mentioned. The invention overcomes certain shortcomings and deficiencies of the prior art. Hard wearing side surfaces are provided on an abrasive blade core, and the service life of the core is comparable with or exceeds the service life of the abrasive segments because of the novel and improved core structure. No undesirable complications have been introduced into the fabrication of abrasive blades, nor have undesirable features been introduced into the finished blades. ture of the invention is such that it is inherently adapted for utilization in practical and effective production. It makes possible the economical production of highly effective wear resistant and durable abrasive cutting blades.

Although specific embodiments of the present invention have been described and illustrated in detail, it is to be clearly understood that the same are by way of illustration and example only; it is to be understood that the invent-ion is not limited thereto, as many variations will be readily apparent to those versed in the art and the invention is to be given its broadest possible interpretation within the terms of the appended claims.

The inventors claim:

1. An abrasive cutting blade comprising a core having two sides and an edge, said core having a concentrically disposed reduced portion thinner throughout than the unreduced portion thereof, said reduced portion defining corresponding 'annularly recessed an'd radially co-extensive depressions in the two sides of the core; hard facing material filling each of said depressions to provide hard material surfaces, said hard surfaces cooperating with the respective core sides to define core side surfaces, and abrasive cutting means other than said facing material attached to said peripheral edge, whereby the abrasive cutting blade is provided with wear resistant side surfaces.

2. An abrasive cutting blade comprising a core having sides and an edge, said core having a reduced portion defining a substantially continuous circumferentially extending depression in each of the sides adjacent to the edge, a substantially continuous body of hard facing ma- The naterial welded in and filling each of said depressions and cooperating with the respective core sides to define core side surfaces, said bodies of hand facing material having side faces substantially flush with said core and having edges cooperating with said reduced core portion to define a peripheral surface, and abrasive cutting means other than said facing material attached to said peripheral surface, whereby the abrasive cutting blade is provided with wear resistant side surfaces.

3. An abrasive cutting blade comprising a steel core having sides and a peripheral edge surface, said core having a plurality of slots spaced along and extending inwardly from said peripheral edge surface said core having a reduced portion defining a continuous circumferentially extending depression in each respective side between the spaced slots, a continuous body of hard metal alloy filling each of said depressions between the spaced slots and cooperating with the respective core sides to define plane side surfaces substantially flush with the sides of the core, and a plurality of abrasive cutting segments attached to said peripheral edge surface between said spaced slots.

4. An abrasive cutting wheel comprising a circular steel core having sides and a circumferential edge, said core having a reduced portion defining first and second annular depressions in the respective sides adjacent to said circumferential edge, a body of hard facing material welded in each of said depressions and cooperating with the respective core sides to define plane side surfaces, said hard facing material including a chrome-tungstencobalt base alloy, said bodies of hard facing material having edges cooperating with said reduced core portion to define a circumferential edge surface, and a plurality of abrasive cutting segments attached to the circumferential edge surface, whereby the abnasive cutting wheel is provided with wear resistant side surfaces.

5. An abrasive cutting wheel comprising a circular steel core having sides and a circumferential edge, said core having a reduced portion defining first and second annular depressions in the respective sides adjacent to said circumferential edge, a body of hard facing material Welded in each of said depressions and cooperating with the respective core sides to define plane side surfaces, said hard facing materials including a chrome-tungstencobalt base alloy, said bodies of hard facing material having edges cooperating with said reduced core portion to define a circumferential edge surface, said core having a plurality of radial slots spaced along and extending inwardly from said circumferential edge, and a plurality of abrasive cutting segments attached to the circumferential edge surface between said slots, whereby the abrasive cutting wheel is provided with wear resistant side surfaces.

6. A method of fabricating an abrasive cutting blade, comprising provided a core blank having sides, cutting a depression in each of said sides, securing a body of hard facing material in each of said depressions, and attaching abrasive cutting means other than said facing material to a peripheral edge of the core, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with the service life of the abrasive cutting means.

7. A method of fabricating an abrasive cutting blade comprising providing a core blank having first and second sides and a peripheral edge, cutting a depression in each of said sides, securing a body of hard facing material in each of said depressions, removing excess hard facing material to define facing material surfaces coplanar with said first and second core sides, and attaching abrasive cutting means to said edge, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting means.

8. A method of fabricating an abrasive cutting blade comprising providing a. core blank having first and second sides and a peripheral edge, cutting a depression in each of said sides, securing a body of hard facing material in each of said grooves, removing excess hard facing material to define facing material surfaces co-planar with said first and second core sides, cutting a plurality of slots spaced along an edge of the core and extending inwardly therefrom, and attaching abrasive cutting segments to said edge between the slots, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

9. A method of fabricating an abrasive cutting blade, comprising providing a core blank having first and second sides and an edge, cutting a groove spaced from the edge in each of said side surfaces, thereby defining a peripheral rim portion, securing a body of hard facing material in each of said grooves, removing the rim portion of the core to provide a peripheral surface defined by the edges of said facing material bodies and by a reduced core portion therebetween, and attaching abrasive cutting means to said peripheral surface, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting means.

10. A method of fabricating an abrasive cutting blade comprising providing a core blank having sides and an edge, cutting a groove spaced from the edge in each of said side surfaces, thereby defining a peripheral rim portion, securing a body of hard facing material in each of said grooves, removing excess hard facing material to define facing material surfaces oo-planar with the respective core sides, removing said rim portion of the core to provide a peripheral surface defined by the edges of said facing material bodies and by a reduced core portion the-rebetween, cutting a plurality of slots spaced along said peripheral edge and extending inwardly therefrom, and attaching abrasive cutting segments to said peripheral surface of the core between the slots, whereby an abrasive cutting blade is formed with Wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

11. A method of fabricating an abrasive cutting blade, comprising providing a core blank having first and second sides, cutting a depression in each of said side surfaces, welding a first body of hard facing material in the depression in said first side, welding a second body of hard facing material in the depression in said second side, and attaching abrasive cutting segments to a peripheral edge surface of the core, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

12. A method of fabricating an abrasive cutting blade, comprising providing a core blank having first and second sides, cutting a depression in each of said side surfaces, welding a first body of hard facing material in the depression in said first side, welding a second body of hard facing material in the depression in said second side, said second facing material having a lower melting point than the first facing material and being weldable without fusion of the welded first body of facing material, and attaching abrasive cutting segments to a peripheral edge surface of the core, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable With that of the abrasive cutting segments.

13. A method of fabricating an abrasive cutting blade, comprising providing a steel core blank having first and second sides and an edge, cutting a depression in each of said side surfaces, Welding a first facing material of chrome-tungsten-cobalt base alloy in the depression in said first side, cooling the core relatively slowly to prevent cracking of said first hard facing material, welding a second facing material of chromium b-orite-nickel alloy in the depression in said second side, said second facing material having a lower melting point than the first facing material and being Weldable without fusion of the welded first body of facing material, cooling the core relatively slowly to prevent cracking of the second hard facing material, and securing diamond cutting segments to a peripheral edge surface of the core, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

14. A method of fabricating an abrasive cutting blade, comprising providing a core blank having first and second sides, cutting a depression in each of said side surfaces, welding a first body of hard facing material in the depression in said first side, cooling the core relatively slowly to prevent cracking of said first hard facing material, welding a second body of hard facing material in the depression in said second side, said second facing material having a lower melting point than the first facing material and being weldable without fusion of the Welded first body of facing material, cooling the core relatively slowly to prevent cracking of the second hard facing material, and attaching abrasive cutting segrnents to a peripheral edge surface of the core, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with at of the abrasive cutting segments.

15. A method of fabricating an abrasive cutting blade, comprising providing a core blank having first and second sides and an edge, cutting a depression in each of said side surfaces, welding a first body of hard facing material in the depression in said first side, cutting a first series of slots spaced along said edge and extending inwardly therefrom, welding a second body of hard facing material in the depression in said second side, said second facing material having a lower melting point than the first facing material and being weldable without fusion of the welded first body of facing material, cutting a second series of slots spaced along said edge and extending inwardly therefrom each of said second series of slots being spaced between adjacent slots of the first series, and attaching abrasive cutting segments to the core between the slots, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

16. A method of fabricating an abrasive cutting blade comprising providing a core blank having first and second sides and an edge, cutting a first annular groove spaced from said edge in the first side, welding a first body of hard facing material in the first groove while the rim portion retains the fused material, removing excess hard facing material to provide a surface co-planar with said first core side, cutting a second annular groove spaced from said edge in the second side surface of the core blank, thereby forming an annular peripheral rim portion, welding a second body of hard facing material in the second groove while the peripheral rim retains the fused material, said second hard facing material having a lower melting point than the first hard facing material and being weldable without fusion of the welded first body of facing material, removing the annular peripheral rim portion to provide a peripheral core surface defined by circiunferential edges of said bodies of facing material and by a circumferential edge of a reduced core portion between the facing material bodies, and attaching abrasive cutting means to said peripheral edge surface between the slots, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting means.

17. A method of fabricating an abrasive cutting blade comprising providing a circular core blank having first and econd sides and a circumferential edge, cutting a first annular groove in the first side and spaced from said edge, thereby defining an annular peripheral rim portion, welding a first body of hard facing material in the first groove while the rim portion retains the fused material, cooling the core relatively slowly to prevent cracking of said first hard facing material, cutting a first series of radial slots spaced along said circumferential edge and extending inwardly therefrom, removing excess hard facing material to provide a surface coplanar with said first core side, cutting a second annular groove in the second side surface of the core blank spaced from said edge and forming .a peripheral rim portion, Welding a second body of hard facing material in the second groove While the peripheral rim retains the fused material, said second hard facing material having a lower melting point than the first hard facing material and being weldable without fusion of the welded first body of facing material, cooling the core relatively slowly to prevent cracking of the second hard facing material, cutting a second series of radial slots spaced on said circumferential edge and extending inward-1y therefrom, each slot of the second series being spaced between adjacent slots of the first series, removing the annular peripheral portions to provide a peripheral core surface defined by circumferential edges of said bodies of facing material and by a circumferential edge of a reduced core portion between the facing material bodies, and attaching abrasive cutting segments to said peripheral edge surface between the slots, whereby an abrasive cutting blade is formed with Wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting segments.

18. A method of fabricating an abrasive cutting blade comprising providing a circular core blank having first and second sides and an edge, cuting first and second annular grooves in the respective sides and spaced from said edge, thereby defining an annular peripheral rim, welding a first body of hard facing material into the first groove while the peripheral rim retains the fused material, cooling the core relatively slowly to prevent cracking of said first bard facing material, cleaning the second groove to remove oxidation and impurities, Welding a second body of hard facing material in the second groove while the peripheral rim retains the fused material, cooling the core relatively slowly to prevent cracking of the second hard facing material, removing excess hard facing material to provide ifac ing material surfaces co-planar with the respective sides of the core blank, removing said annular peripheral rim to provide a peripheral core surface defined by circumferential edges of said bodies of facing material and by a circumferential edge of a reduced core portion between the facing material bodies, and attaching abrasive cutting means to said peripheral edge surface, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting means.

19. A method of fabricating an abrasive cutting blade comprising providing a core blank having first and second sides and an edge, cutting first and second annular depressions in the respective sides adjacent to the edge to define a reduced core portion, Welding a first body of hard facing material in the first depression, Welding a second body of hard facing material in the second depression, removing excess hard facing material to provide facing material surfaces co-planar with the respective sides of the core blank, removing excess hard facing material from the peripheral edge of the core to provide a peripheral edge surface defined by circumferential edges of said bodies of facing material and by the circumferential edge of the reduced core portion between the facing material bodies, and attaching abrasive cutting means to said peripheral edge surface, whereby an abrasive cutting blade is formed with wear resistant side surfaces to insure a core service life comparable with that of the abrasive cutting means.

References Cited in the file of this patent UNITED STATES PATENTS 2,763,258 Hughes Sept. 18, 1956 FOREIGN PATENTS 5,331 Great Britain Jan. 13, 1894 of 1893 

1. AN ABRASIVE CUTTING BLADE COMPRISING A CORE HAVING TWO SIDES AND AN EDGE, SAID CORE HAVING A CONCENTRICALLY DISPOSED REDUCED PORTION THINNER THROUGHOUT THAN THE UNREDUCED PORTION THEREOF, SAID REDUCED PORTION DEFINING CORRESPONDING ANNULARLY RECESSED AND RADICALLY CO-EXTENSIVE DEPRESSIONS IN THE TWO SIDES OF THE CORE; HARD FACING MATERIAL FILLING EACH OF SAID DEPRESSIONS TO PROVIDE HARD MATERIAL SURFACES, SAID HARD SURFACES COOPERATING WITH THE RESPECTIVE CORE SIDES TO DEFUINE CORE SIDE SURFACES, AND ABRASIVE CUTTING MEANS OTHER THAN SAID FACING MATERIAL ATTACHED TO SAID PERIPHERAL EDGE, WHEREBY THE ABRASIVE CUTTING BLADE IS PROVIDED WITH WEAR RESISTANT SIDE SURFACES. 